EP 0 197 449 B1 has disclosed a multi-part reciprocating piston for internal combustion engines, which in particular has a Scotch yoke mechanism and is rigidly connected to a piston rod. This piston includes a piston skirt that has a piston skirt base and is composed of a ceramic material, e.g. zirconium oxide, silicon nitride, or silicon carbide, in particular Si—SiC, and includes a piston base that has a head land and is likewise made of ceramic material and is provided with an annular groove for accommodating a split piston ring composed of a ceramic material. The piston base rests against the piston skirt base and the two main parts of the piston are radially fixed by means of a shared centering sleeve, likewise composed of ceramic material. The reciprocating piston also has a centering piece that is fixed on the piston rod with a snug fit and is composed of metal or of a metal alloy, with a base plate on which the piston skirt base rests and with an end cover that is made of the same material as the centering piece and rests against the piston base while extending radially to its head land. The end cover has a centering hub that is radially fixed relative to the centering piece, with an axial spacer gap between the two parts; the piston skirt base and the piston base are axially clamped between the end cover and the base plate by a screw connection associated with the piston rod. Because of the two-part embodiment, it is also possible to use piston rings composed of a ceramic material. This arrangement has proven useful.
DE 33 03 229 A1 has disclosed a ceramic internal combustion engine without piston lubrication, having a ceramic piston that travels in linear fashion in a ceramic cylinder; there is no contact between the ceramic piston and ceramic cylinder; instead, an annular gap is provided between them.
WO 00/25012 A1 has disclosed a carbon piston for an internal combustion engine. For example, piston rings composed of carbon can be used as piston rings for the piston. Also according to WO 00/25012 A1, the cylinder in which the carbon piston travels for example has a ceramic cylinder bushing, for example. The particular advantage of the carbon piston is that it has good limp-home properties.
The object of the present invention is to create a ceramic reciprocating piston for a reciprocating piston machine, in particular a reciprocating piston engine, having a crank mechanism, preferably a Scotch yoke mechanism, and having a piston rod rigidly connected to the reciprocating piston; a secure, permanent connection should be ensured, even during operation of the reciprocating piston machine.
Another object of the invention is to create a reciprocating piston machine equipped with such a reciprocating piston.
Another object of the invention is to create a cylinder of a reciprocating piston machine, in particular a reciprocating piston engine, having a crank mechanism, preferably a Scotch yoke mechanism, having at least one ceramic cylinder bushing situated in a cylinder bore of the cylinder, and having a ceramic reciprocating piston that is guided so that it can reciprocate in the cylinder bushing; a penetration of oil from the crank mechanism into the combustion chamber should be avoided and a long service life of the reciprocating piston machine should be ensured.